1. Field of the Invention
The present invention refers to a flow indicator to indicate direction of airflow between two rooms.
2. Description of the Related Art
Within many buildings, as industrial departments, laboratories etc., it is of importance to know the direction of the airflow between two rooms. In manufacturing of pharmaceuticals, as for an example, this information is essential to prevent contaminated airflow in the wrong direction. The flow indicators that are known have solved this with a xe2x80x9cflapxe2x80x9d or other suitable means in an opening between the rooms to show the direction of the airflow. A disadvantage is, however, that if an airflow is obtained in the wrong direction, unacceptable air will flow in to the protected room before any steps to change the direction of the flow or the pressure difference has been taken.
The object of the present invention is to achieve a flow indicator that eliminates the disadvantages mentioned above in connection with known flow indicators.
This task is solved by giving the flow indicator according to the invention the characteristics of including a tube communicating with two rooms through a sealed passageway and in which a body is movable by differential air pressure or airflow and wherein the body is engageable with seals in the ends of the tube to thereby prevent airflow through the tube in the direction of the airflow.